P-51D performance

[billeinstein]

Er, the Carburetor Air Temperature supposed to be this:(picture from A2A sim).

"Supercharging Heats The Air

The downside to supercharging is heat. The more you compress air, the more the temperature increases, therefore more supercharging = higher CAT temperatures. The increase in temperature can be extreme. -40 degree air coming into the intake system can be 100 degrees hotter after it exits the supercharger. This is where your INTERCOOLER comes into play. The INTERCOOLER is a heat exchange, and is basically a radiator taking heat out of the incoming air. Use your INTERCOOLER FLAPS to transfer heat out of your intake manifold and out the flap doors. The more you open your intercooler flaps, the more heat you remove. Use your intercooler flaps to keep CAT temps nice and low for a strong and healthy running engine."

 

And in DCS manual:

"The AN5790-6 Carburetor Air Temperature Indicator shows the temperature of the air running through the carburetor air scoop. The gauge indicates temperature in degrees Celsius (°C) and is graduated from - 70° to 150°C. The face is scaled to 10°C. The green range indicates normal operating temperature of 10° - 30°C. The Red Line indicates maximum temperature of 40°C."

Edited November 3, 2012 by billeinstein

[Yo-Yo]

Er, the Carburetor Air Temperature supposed to be this:(picture from A2A sim).

"Supercharging Heats The Air

The downside to supercharging is heat. The more you compress air, the more the temperature increases, therefore more supercharging = higher CAT temperatures. The increase in temperature can be extreme. -40 degree air coming into the intake system can be 100 degrees hotter after it exits the supercharger. This is where your INTERCOOLER comes into play. The INTERCOOLER is a heat exchange, and is basically a radiator taking heat out of the incoming air. Use your INTERCOOLER FLAPS to transfer heat out of your intake manifold and out the flap doors. The more you open your intercooler flaps, the more heat you remove. Use your intercooler flaps to keep CAT temps nice and low for a strong and healthy running engine."

 

And in DCS manual:

"The AN5790-6 Carburetor Air Temperature Indicator shows the temperature of the air running through the carburetor air scoop. The gauge indicates temperature in degrees Celsius (°C) and is graduated from - 70° to 150°C. The face is scaled to 10°C. The green range indicates normal operating temperature of 10° - 30°C. The Red Line indicates maximum temperature of 40°C."

 

Hate saying it but you did not read the manual carefully. In P-51 this gauge sensor measures the carburettor intake temperature. The blower has no deal with this temperature because in P-51 sequence is carb intake - carb injector - blower1 - intercooler - blower2 - aftercooler - manifold.

[billeinstein]

Follow your point, the hot air control shall work as a carb heater, and the C.A.T Indicator is for ice detection. But why the high temp limit is 40C for the intake?

I'd rather think it measures whether the intercooler and aftercooler work fine or not. If they failed, temp will rise and the engine shall die. I'm Still seeking info to prove this wrong or not.

[Yo-Yo]

Follow your point, the hot air control shall work as a carb heater, and the C.A.T Indicator is for ice detection. But why the high temp limit is 40C for the intake?

I'd rather think it measures whether the intercooler and aftercooler work fine or not. If they failed, temp will rise and the engine shall die. I'm Still seeking info to prove this wrong or not.

 

It's obviously WRONG - how can you measure outside temperature if the thermometer is mount inside your bathroom???

 

High carb intake temperature causes manifold temperature increasing so you can discover something like detonation at full power...

Edited November 3, 2012 by Yo-Yo

[billeinstein]

It's obviously WRONG - how can you measure outside temperature if the thermometer is mount inside your bathroom???

 

High carb intake temperature causes manifold temperature increasing so you can discover something like detonation at full power...

"Hot air should not be used above 12,000 feet. At high altitudes its use affects the carburetor’s altitude compensation and may result in an overly lean fuel mixture."

 

-This means the C.A.T Indicater is useless over 12000ft. Nothing else (except fire) can warm up the intake over 40C at that altitude.

 

And if I lose the coolant in the after-cooling system, the C.A.T Indicater just reads cool, and no gauge will warn me about it untill the engine failure. That's too bad...:cry:

 

There's a "rumor" said that the merlin engine of P-51D inject the fuel directly into the blower, preventing it from icing...

[Yo-Yo]

"Hot air should not be used above 12,000 feet. At high altitudes its use affects the carburetor’s altitude compensation and may result in an overly lean fuel mixture."

 

-This means the C.A.T Indicater is useless over 12000ft. Nothing else (except fire) can warm up the intake over 40C at that altitude.

 

And if I lose the coolant in the after-cooling system, the C.A.T Indicater just reads cool, and no gauge will warn me about it untill the engine failure. That's too bad...:cry:

 

There's a "rumor" said that the merlin engine of P-51D inject the fuel directly into the blower, preventing it from icing...

 

If you have AK down detonation will be detected as black smoke goes from the stack. If you reduce rpm and MP you can proceed.

Carburettor Ventury tubes (throat) are more prone to icing then blower that rises the temperature.

[Yo-Yo]

Probably you have found a bug with rammed air... we have no idea how this feature was not included in public project though it was implemented long ago and lives in current version.

 

Sorry for my interrogation but I had to be sure that the problem really exists... :) then you have learnt many facts about the pony.

Edited November 3, 2012 by Yo-Yo